GB2065979A

GB2065979A - Stepwise Advance Device for a Cam Programmer

Info

Publication number: GB2065979A
Application number: GB8039856A
Authority: GB
Original assignee: OMP OFF MECCANO PLAST
Current assignee: OMP OFF MECCANO PLAST
Priority date: 1979-12-13
Filing date: 1980-12-12
Publication date: 1981-07-01
Also published as: ES497595A0; DE3045230A1; ES8106970A1; GB2065979B; FR2472229A1; IT7945732A0; IT1125083B

Abstract

A stepwise advance device (6) engaging a pinion (8) of the cam pack (5) of a programmer, has a time-delay memory wheel (10) which is intermittently driven in reverse by clutch means (25-28) when the stepping advance means (6) is disengaged at the start of a pause period as by cam (16) on a fast cam 18. The memory wheel (10) has a stepped profile (20) co-operating with an enabling lever (21) in combination with projections (24) of preselected lengths on a time-delay cam (23) on the cam pack (5) to determine the angles of reverse rotation. The number of steps of the profile (20) determines the number of different pause times which can be obtained, while the height of the projections (24) of the time-delay cam (23) determines the duration of each pause time by limiting the reverse rotation of the wheel 10 and thereby the number of teeth (9) which must be stepped forward by the advance device (6) before it drops back onto the pinion 8 to advance it to the next step. <IMAGE>

Description

SPECIFICATION Stepwise Advance Device for a Cam Programmer The present invention relates to a stepwise advance device for a programmer, for example of the type which can be used in automatic washing machines, with differentiated advance times.

As is known, such programmers essentially comprise a group of fast actuating cams and a pack of slow program cams which are entrained by the first cams with stepwise advance movements spaced by pause periods.

For the purposes of carrying out different programs with phases of differentiated durations, programmers of the above-quoted type have been proposed, which are provided with stepwise advance devices having pause times which are different and selectively interchangeable in dependence on the characteristics of the programs which can be laid down. This means that the pack of slow cams of a programmer may be associated with different advance devices for the purposes of carrying out programs with different and differently distributed pause times.

Such advance devices are normally complicated from the structural and functional point of view and suffer from the main disadvantage that they must be completely replaced whenever it is desired to provide the programmer with a different number of different pause times, or pause times which are differently distributed within the programs which can be laid down.

Consequently, the programmers of this type, the structural complexity of which is compensated by potential functional versatility, in practice cannot bye used for the more varied uses because, as already stated, in some cases they require complete replacement of the stepwise advance device, which is a basic component of the programmer.

According to the present invention, there is provided an advance device for the cam pack of a programmer, comprising a toothed wheel which is fixed in respect of rotation of said cam pack and which is capable of being stepwise actuated by time-delayed advance means; and a memory wheel which is free to rotate and which is provided with a toothed sector and which is actuable for reverse rotary movement with respect to that of the cam pack, by way of clutch means synchronised with said advance means, into a position in which the toothed sector cooperates with the advance means, preventing engagement thereof with said toothed wheel, the memory wheel also being provided with a stepped profile with which there co-operates an edge of a spring-loaded enabling lever which is capable of stopping against said profile, blocking reverse rotary movement of the memory wheel and overcoming the force of said clutch means, when the opposite edge of said enabling lever bears against the profile of a time-delay cam which is fixed in respect of rotation to the toothed wheel, the advance device further comprising a control cam capable of rotating synchronously with said clutch means and provided with a pause profile capable of moving said advance means into an inoperative position when the memory wheel is actuated for reverse rotary movement.

As will be apparent from the description below, the illustrated embodiment of the present invention provides a stepwise advance device for a programmer which is simple in construction and versatile in use, and which can be used, by substitution of a single component, to produce a high and variable number of different pause times, and pause times which have a different time distribution within a program.

The features and advantages of the present invention will be apparent from the following description given by way of non-limiting example with reference to the accompanying drawings in which: Figures 1 to 3 show diagrammatic views in partial section of a stepwise advance device according to the invention, in respective operating positions; and Figure 4 shows a partly sectional side view of the advance device of Figure 1.

Referring to the drawings, the advance device is intended to be mounted on a programmer, associated with a slow or program cam pack 5, which cams are to be entrained with a stepwise motion (in a clockwise direction) by means of a spring-loaded advance pawl 6. The pawl 6 is pivoted eccentrically on the support frame 7 of the programmer and is intended to be actuated in known manner by a small control motor (not shown); for example, the pawl 6 is arranged to perform an advance movement each minute, which may be considered as a time base. For such advance movement, the pawl 6 normally cooperates with a toothed wheel 8 which is fixed with respect to the cam pack 5 (Figure 1). In the operative position of Figure 3, the pawl 6 on the other hand is capable of co-operating with a toothed sector 9 of a memory wheel 10 which is concentric with the toothed wheel 8 and free to rotate.

The diameter of the internal circumference of the sector 9 is larger than the diameter of the external circumference of the toothed wheel 8, while the remainder of the profile of the memory wheel 10 is of a diameter which is equal to or less than the internal diameter of the toothed wheel 8 and is provided with a plain portion 11 and with a toothed portion 1 2 at a suitable angular position.

The diameter of the plain portion 11 is at least equal to the diameter of the external circumference of the toothed portion 12.

The portions 11 and 12 of the memory wheel 10 are capable of co-operating with a springloaded sensor 13 which is pivoted on the support frame 7. The advance pawl 6 and the sensor 13 are provided with respective L-shaped slider or skid portions 14 and 1 5 which are capable of respectively co-operating with at least one circular pause segment 1 6 and with at least one circular release segment 1 7. The segments 1 6 and 17 are of different diameters and are formed integrally, projecting axially from a fast cam 18 which is actuated in the clockwise direction by the control motor in synchronisation with the advance pawl 6.In addition, the ends of the segments 1 6 and 17 which co-operate with the slider portions 14 and 1 5 of the segments 16 and 1 7 are so shaped as to cause the slider portions 14 and 15 to engage the external surface of the segments.

The memory wheel 10 is provided with a shaped opening 19 with a profile 20 with bevelled steps, the diameter thereof decreasing in discrete levels in a clockwise direction. The steps of the profile 20 subtended angles which are identical to each other and corresponding to the pitch of the teeth of the sector 9 and the toothed wheel 8. As will be more clearly apparent hereinafter, the number of steps of the profile 20 corresponds to the maximum number of different pause times for which the advance device may be set up.

In consequence, it is preferable for the number of such steps to be relatively high.

The end of an enabling lever 21 co-operates with the profile 20. The lever 21 is pivoted on the supportframe 7, is of a L-shaped configuration, and is urged by a spring 22 constantly into abutment against the above-mentioned profile 20. The advance device further comprises a timedelay cam 23 which is concentric to and fixed in respect of rotation with the cam pack 5.

The profile of the time-delay cam 23 comes to lie at the position of the openlng 19 and is capable of co-operating with the lever 21. The profile of the cam 23 is preferably shaped with teeth 24 which are of a suitable radial length of a pitch corresponding to the pitch of the teeth of the sector 9. As will be more-clearly apparent hereinafter, the radial length of each tooth 24 corresponds to the duration of a respective pause time which can be laid down by the advance device.

A front surface of the memory wheel 10 is provided with a zero-setting tooth assembly 25 by means of which it can be entrained in rotation by a similar tooth assembly 26 of the fast cam 18, by way of a pinion mechanism. This mechanism comprises a first pinion 27 which is capable of engaging the tooth assembly 26 and a second pinion 28 which is capable of engaging the tooth assembly 25.

The pinions 27 and 28 are coaxiai and provided with frontal or face teeth by means of which they co-operate together for rotary movement. In addition, at least the pinion 28 is axially movable and, whenever the memory wheel 10 is locked, the pinion 28 can become disengaged from the pinion 27 by overcoming the force of a spring 29 which tends to hold it in position.

In operation, it will be assumed that the advance device is in the position shown in Figure 1 in which the pawl 6 is in engagement with the toothed wheel 8 and bears against the toothed sector 9. In its movement in an eccentric mode, the pawl 6 can thus advance the wheel 8 (with the cam pack) and the memory wheel 10, by one step. In consequence, the sensor 13 goes from the toothed portion 12 and co-operates with the plain portion 11 of the wheel 10, lifting the slider portion 15.

The portion 1 5 comes to lie in a position corresponding to the shaped end of the release segment 1 7 which, by virtue of the clockwise direction of the fast cam 18, lifts it further so as to disengage the wheel 10 from the sensor 1 3. At the same time, the rotary movement of the fast cam 1 8 causes the pause segment 1 6 to lift the slider portion 14, disengaging the pawl 6 from the toothed wheel 8 and the memory wheel 10. As shown in Figure 2, the memory wheel 10 can thus rotate in an anti-clockwise direction by the combined action of the tooth assemblies 25 and 26 and the pinion mechanism 27 and 28.

During the rotary movement of the wheel 10, the enabling lever 21 follows the stepped profile 20 of the opening 19, being moved with respect to the fulcrum, if movement thereof towards the centre is not impeded by one of the teeth 24 of the time-delay cam 23, in particular that whichh is adjacent to the end of the lever.

The memory wheel 10 thus continues to rotate until the end of the lever 21 is engaged between the adjacent tooth 24 and the profile 20, stopping against the corresponding step of the profile 20 and blocking the anti-clockwise rotary movement of the memory wheel 10. As may be noted, the angle of anti-clockwise rotation of the toothed sector 9 depends on the radial length of the tooth 24 with which the end of the lever 21 co-operates in this phase.

After the wheel 10 is blocked, the pinion 28 can no longer be driven in rotation by the tooth assembly 26 and the pinion 27, whereby it is repeatedly displaced in the axial direction, overcoming the force of the spring 29 and performing like a friction clutch in a slipping condition.

In the meantime, the rotary movement of the cam 18 moves the segments 16 and 17 into a position in which they are disengaged from the portions 14 and 1 5 whereby the pawl 6 can engage with the toothed sector 9 and the sensor 1 3 can rotate into engagement with the toothed profile 12 of the memory cam 10, as shown in Figure 3.

Because the teeth 24 of the time-delay cam are preferably laterally bevelled to permit forced displacement of the lever 21 thereover (the lever 21 is so mounted that it can bend vertically with respect to the plane of Figure 3) during the manual actuating operations of the programmer, the sensor 13 is provided to perform the function of preventing any further and accidental anticlockwise rotary movement of the memory wheel 10. For example, such accidental rotary movement could be caused by the pinion transmission 25-28 or the movement of the pawl 6.

In the embodiment shown in Figure 3, the pawl 6 co-operates in this phase with the seventh tooth (in the clockwise direction) of the toothed sector 9. This is because the angle of anticlockwise rotation of the memory wheel 10 determines the pause time (in this case 7 minutes) which elapses between the previous and the subsequent step advance movement of the cam pack 5. In fact, with its eccentric movement, the pawl 6 causes only the toothed sector 9 to advance by one step each minute (time base), in a clockwise direction.

In this phase, the sensor 1 3 passes freely over the toothed profile 12 of the memory wheel 10, it is only when the pawl 6 is gradually disengaged from the tooth assembly of the sector 9, by returning to the position shown in Figure 1, that it can again co-operate with the toothed wheel 8 and produce successive advance movements of one step of the cam pack 5, and also the timedelay cam 23.

Thus, the mode of operation of the advance device takes place in a similar manner to that described hereinbefore, with a fresh pause time which may be equal to or different from the previous time, in dependence on the radial length of the tooth 24 which has now come to lie at the position of the end of the lever 21.

The foregoing description clearly shows the structural and functional simplicity of the advance device according to the invention, which makes it possible to provide for pause times of extremely different durations.

A factor of basic importance is that the same advance device can be used for performing not only a different number of pause times, but also pause times of variable duration, simply by modifying the profile of the time-delay cam 23, in particular the radial length of the teeth 24.

Obviously, the above-described device may be the subject of many modifications, for example relating to synchronisation of the movements, as likewise it may be put to various uses, subject to the particular characteristics claimed hereinafter.

Claims

1. An advance device for the cam pack of a programmer, comprising a toothed wheel which is fixed in respect of rotation to said cam pack and which is capable of being stepwise actuated by time-delayed advance means; and a memory wheel which is free to rotate and which is provided with a toothed sector and which is actuable for reverse rotary movement with respect to that of the cam pack, by way of clutch means synchronised with said advance means, into a position in which the toothed sector cooperates with the advance meanspreventing engagement thereof with said toothed wheel, the memory wheel also being provided with a stepped profile with which there co-operates an edge of a spring-loaded enabling lever which is capable of stopping against said profile, blocking reverse rotary movement of the memory wheel and overcoming the force of said clutch means, when the opposite edge of said enabling lever bears against the profile of a time-delay cam which is fixed in respect of rotation to the toothed wheel, the advance device further comprising a control cam capable of rotating synchronously with said clutch means and provided with a pause profile capable of moving said advance means into an inoperative position when the memory wheel is actuated for reverse rotary movement.

2. An advance device according to claim 1 wherein said memory wheel is concentric with said toothed wheel, the diameter of the external circumference of which is smaller than the diameter of the internal circumference of said toothed sector.

3. An advance device according to claim 1,2 or 3 wherein said clutch means comprise a first pinion capable of engaging a tooth assembly of said control cam and'a second pinion which is capable of engaging a tooth assembly of the memory wheel and co-operating for rotary movement, by means of respective face teeth, with the first pinion, at least one of said pinions being axially movable, overcoming the force of a spring, to cause the face teeth to move over each other when the memory wheel is blocked by said enabling lever.

4. An advance device according to claim 1,2 or 3 wherein said advance means comprise an eccentric-actuated spring-loaded pawl fixed with respect to a slider portion capable of co-operating with said pause profile of the control cam.

5. An advance device according to claim 1, 2, 3 or 4, wherein said stepped profile is provided in the form of an opening in the memory wheel, which is disposed in association with the profile of the time-delay cam.

6. An advance device according to any one of the preceding claims wherein said enabling lever is loosely pivoted on a support frame and the profile of said time-delay cam is shaped with teeth having at least one side which is bvelled to permit said lever to pass forcibly thereover.

7. An advance device according to claim 6 wherein the profile of said memory wheel comprises a toothed portion and a plain portion, the diameter of which is greater than or equal to that of the external circumference of the toothed portion, the latter normally being capable of cooperating with a spring-loaded sensor which is pivoted on the frame and which is provided with a normally free slider portion, the sensor being capable of co-operating with said plain portion when said advance means engage the tooth wheel moving said slider portion into a position in which it is capable of disengaging the sensor from the profile of the memory wheel when the latter is actuated in the reverse direction.

8. An advance device constructed and arrange to operate substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

9. A cam-operated programmer incorporating a device according to any one of the preceding claims.

10. A domestic appliance incorporating a programmer according to claim 9.